Submission #3882199

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Source Code Expand

input = __import__('sys').stdin.readline
MIS = lambda: map(int,input().split())

n, m = MIS()
adj = [[] for i in range(n+1)]
speaker = [[] for i in range(m+1)]
for i in range(n):
    lang = list(MIS())[1:]
    for x in lang: speaker[x].append(i+1)
for L in speaker:
    for i in range(len(L)-1):
        adj[L[i]].append(L[i+1])
        adj[L[i+1]].append(L[i])

vis = [False]*(n+1); vis[1] = True
stack = [1]
while stack:
    p = stack.pop()
    for q in adj[p]:
        if vis[q]: continue
        vis[q] = True; stack.append(q)
print("YES" if sum(vis) == n else "NO")

Submission Info

Judge Result